Fan, motor and bearing structure thereof

ABSTRACT

A bearing structure which is cooperated with a shaft and is disposed in a bearing tube comprises an oil bearing and a cylindrical sealing member. The oil bearing has an axial hole. The shaft passes through the axial hole. The cylindrical sealing member covers a top surface and at least a portion of a sidewall of the oil bearing. The cylindrical sealing member has a through hole defined in its center. The shaft passes through the through hole.

CROSS REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. §119(a)on Patent Application No(s). 095109135 filed in Taiwan, Republic ofChina on Mar. 17, 2006, the entire contents of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a fan, a motor and a bearing structure thereof,and in particular, to a fan, a motor and a bearing structure thereofcapable of preventing oil leakage.

2. Related Art

Many apparatuses (e.g., fans) use motors to transmit power. Accordingly,the quality of the motor greatly influences the quality of theapparatus. If the motor works unstably, the operation of the overallapparatus will be inevitably influenced. The bearing in the motor is oneof the key factors to influence the quality of the motor.

The conventional motor frequently uses a ball bearing. However, the ballbearing has a high cost, cannot resist the impact of exterior force, andcannot provide the sufficient lubrication while rotating at a highspeed. Thus, the prior art uses an oil bearing to replace the ballbearing. However, when the oil bearing is mounted on a bearing tube, asufficient combining force has to be applied to prevent the axialdetachment of the shaft. The combining force is directly applied to theoil bearing to make the aperture in the oil bearing shrink. Thus, thewear between the shaft and the oil bearing becomes serious, and thelifetime of the product is shortened.

The typical oil bearing is made of a porous material, in which aplurality of micro voids is formed and lubrication oil is containedtherein. When a shaft is rotating in the oil bearing, the capillaryphenomenon of the micro voids draws the lubrication oil into a gapbetween the shaft and the oil bearing, thereby lubricating the shaft andthe oil bearing. However, because the shaft wears against the oilbearing for a long period of time, the lubrication oil evaporates andtransforms at the high temperature and thus influences the lubricationfunction of the oil bearing. When the motor operates in an upside-downmanner, the lubrication oil leaks from the gap between the shaft and theoil bearing due to gravity and cannot be recycled, causing insufficientlubrication.

As shown in FIG. 1, a conventional oil bearing 10 has an axial hole 101for telescoping a shaft 11 therein. The oil bearing 10 is disposed in abearing tube 12 of a stator seat. Because a top surface 102 of the oilbearing 10 directly contacts the air on the outside, the lubricationoil, which is driven by the rotating shaft 11, leaks to the outside fromthe top surface 102 of the oil bearing 10, the gap between the oilbearing 10 and the shaft 11, and the gap between the oil bearing 10 andthe bearing tube 12. In particular, when the oil bearing 10 is used inan upside-down manner, the leakage condition becomes more serious suchthat the lifetime of the oil bearing 10 is shortened. Alternatively, theresultant lack of lubrication oil causes the overall operation to becomerough, or causes the oil bearing to become damaged by the frictionalforce between the shaft and the oil bearing.

In order to solve this problem, as shown in FIG. 2, an annular flatbaffle 13 is disposed on the top surface 102 of the oil bearing 10 inthe prior art so as to interrupt the leakage path of the lubricationoil. However, the effect of this method is limited. The lubrication oilstill leaks outward from the gap between the oil bearing 10 and theshaft 11, the gap between the baffle 13 and the shaft 11 and the gapbetween the oil bearing 10 and the bearing tube 12.

Thus, it is desired to provide a fan, a motor and a bearing structurethereof capable of effectively preventing the problem of oil leakage andthus lengthening the lifetime of the fan, motor and oil bearing.

SUMMARY OF THE INVENTION

In view of the foregoing, the invention is to provide a fan, a motor anda bearing structure thereof capable of effectively preventing theproblem of oil leakage and thus lengthening the lifetimes of the fan,motor and oil bearing.

To achieve the above, the invention discloses a bearing structurecooperated with a shaft, and the bearing structure is disposed in abearing tube. The bearing structure comprises an oil bearing and acylindrical sealing member. The oil bearing has an axial hole. The shaftpasses through the axial hole. The cylindrical sealing member covers atop surface of the oil bearing and at least a portion of a sidewall ofthe oil bearing, and is connected with an inner wall of the bearingtube. The center of the cylindrical sealing member has a hole for theshaft passed therethrough.

To achieve the above, the invention also discloses a bearing structurecooperated with a shaft, and the bearing structure disposed in a bearingtube. The bearing structure comprises an oil bearing and a sealingmember. The oil bearing has an axial hole. The shaft passes through theaxial hole. The sealing member covers a top surface of the oil bearing.The sealing member has a through hole defined in its center. The shaftpasses through the through hole, and an inner wall of the through holeis formed with at least one groove.

To achieve the above, the invention discloses a motor, which comprises arotor structure, a stator structure, and a bearing structure. The rotorstructure has a shaft, and the stator structure has a bearing tube. Thebearing structure is disposed in the bearing tube and comprises an oilbearing and a cylindrical sealing member. The oil bearing has an axialhole. The shaft passes through the axial hole. The cylindrical sealingmember covers a top surface of the oil bearing and at least a portion ofa sidewall of the oil bearing, and is connected with an inner wall ofthe bearing tube. The cylindrical sealing member has a through holedefined in its center. The shaft passes through the through hole.

To achieve the above, the invention also discloses a motor, whichcomprises a rotor structure, a stator structure, and a bearingstructure. The rotor structure has a shaft, and the stator structure hasa bearing tube. The bearing structure is disposed in the bearing tubeand comprises an oil bearing and a sealing member. The oil bearing hasan axial hole. The shaft passes through the axial hole. The sealingmember covers a top surface of the oil bearing. The sealing member has athrough hole defined in its center. The shaft passes through the throughhole, and an inner wall of the through hole is formed with at least onegroove.

To achieve the above, the invention discloses a fan, which comprises animpeller, a rotor structure, a stator structure, and a bearingstructure. The impeller has a hub and at least one blade disposed aroundthe hub. The rotor structure has a shaft connected with the hub, and thestator structure has a bearing tube. The bearing structure is disposedin the bearing tube and comprises an oil bearing and a cylindricalsealing member. The oil bearing has an axial hole. The shaft passesthrough the axial hole. The cylindrical sealing member covers a topsurface of the oil bearing and at least one portion of a sidewall of theoil bearing, and is connected with an inner wall of the bearing tube.The cylindrical sealing member has a through hole defined in its center.The shaft passes through the through hole.

To achieve the above, the invention also discloses a fan, whichcomprises an impeller, a rotor structure, a stator structure, and abearing structure. The impeller has a hub and at least one bladedisposed around the hub. The rotor structure has a shaft connected withthe hub, and the stator structure has a bearing tube. The bearingstructure is disposed in the bearing tube and comprises an oil bearingand a sealing member. The oil bearing has an axial hole. The shaftpasses through the axial hole. The sealing member covers a top surfaceof the oil bearing. The sealing member has a through hole defined in itscenter. The shaft passes through the through hole, and an inner wall ofthe through hole is formed with at least one groove.

As mentioned above, the fan, the motor and the bearing structure thereofaccording to the invention use the cylindrical sealing member or thesealing member with the groove to cover the oil bearing. Thus, theleakage path of the lubrication oil can be surely interrupted, so thatthe oil leakage can be avoided, and the lifetime of the oil bearing canbe lengthened.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detaileddescription given herein below illustration only, and thus is notlimitative of the present invention, and wherein:

FIG. 1 is a schematic illustration showing a conventional oil bearingcooperated with a shaft;

FIG. 2 is a schematic illustration showing the oil bearing of FIG. 1having a top surface on which a sealing baffle is disposed;

FIG. 3 is a schematic illustration showing a bearing structurecooperated with a shaft and a bearing tube according to a firstembodiment of the invention;

FIGS. 4A and 4B are schematic illustrations showing different aspects ofa cylindrical sealing member of the bearing structure of FIG. 3;

FIG. 5 is another schematic illustration showing the bearing structureof FIG. 3 having a groove formed on an inner wall of a through hole ofthe cylindrical sealing member;

FIG. 6 is a schematic illustration showing a cover disposed on thebearing structure of FIG. 3;

FIG. 7 is a schematic illustration showing at least one protrusionformed on the inner wall of the cylindrical sealing member of thebearing structure of FIG. 3;

FIG. 8 is a schematic illustration showing a bearing structurecooperated with a shaft and a bearing tube according to a secondembodiment of the invention;

FIG. 9 is a schematic illustration showing a motor according to thepreferred embodiment of the invention; and

FIG. 10 is a schematic illustration showing a fan according to thepreferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings,wherein the same references relate to the same elements.

As shown in FIG. 3, a bearing structure 2 according to a firstembodiment of the invention is cooperated with a shaft 31 and isdisposed in a bearing tube 32. When the bearing structure 2 is appliedto a motor, the shaft 31 can be a shaft of a rotor structure of themotor, and the bearing tube 32 can be a bearing tube of a statorstructure of the motor.

In this embodiment, the bearing tube 32 can be integrally formed. Thatis, the bearing tube 32 is an integrated member. In addition, a bottomportion of the bearing tube 32 has a wear-resisting structure 321 (e.g.,a wear-resisting sheet). Of course, the bearing tube 32 can be composedof a plurality of components in another embodiment. For example, thebottom portion of the bearing tube 32 has an opening, which is sealed bya locking member.

The bearing structure 2 comprises an oil bearing 21 and a cylindricalsealing member 23. The oil bearing 21 has an axial hole 211, and theshaft 31 passes through the axial hole 211. The oil bearing 21 containsthe lubrication oil and can release the lubrication oil for lubricationas the shaft 31 rotates.

The cylindrical sealing member 23 covers a top surface 212 and asidewall 213 of the oil bearing 21. The cylindrical sealing member 23 isdisposed in the bearing tube 32 and is connected to an inner wall of thebearing tube 32. In this embodiment, the cylindrical sealing member 23completely covers, without limitation, the sidewall 213 of the oilbearing 21. However, the cylindrical sealing member 23 can also onlycover a portion of the sidewall 213 of the oil bearing 21.

In addition, the cylindrical sealing member 23 has a through hole 231defined in its center. The diameter of the through hole 231 issubstantially equal to or greater than that of the axial hole 211. Whenthe cylindrical sealing member 23 covers the oil bearing 21, the shaft31 can pass through the through hole 231 and the axial hole 211, andrest against the wear-resisting structure 321.

In this embodiment, the cylindrical sealing member 23 covers the topsurface 212 and the sidewall 213 of the oil bearing 21 to form a closedspace to prevent the lubrication oil from leaking from the top surface212 of the oil bearing 21 and the gap between the oil bearing 21 and thebearing tube 32. Because the pressure in the bearing structure 2 issmaller than the atmospheric pressure, it is possible to prevent thelubrication oil from leaking from the gap between the shaft 31 and theoil bearing 21 under the action of the atmospheric pressure, tocompletely avoid the oil leakage, to effectively hold the lubricationoil within the bearing structure 2 and thus to lengthen the lifetime ofthe bearing structure 2.

In addition, FIGS. 4A and 4B are schematic illustrations showingdifferent aspects of the cylindrical sealing member of the bearingstructure of FIG. 3. The difference between FIG. 4A or 4B and FIG. 3 isthat the cylindrical sealing member 23 has a stepped portion such that aspace 232 (see FIG. 4A) is formed between the cylindrical sealing member23 and the top surface 212 of the oil bearing 21. Alternatively, aninner wall 233 of the top surface of the cylindrical sealing member 23has a concave portion 234 (see FIG. 4B). The space 232 or the concaveportion 234 stores the lubrication oil leaked from the oil bearing 21.In addition, the pressure in the space 232 or the concave portion 234 issmaller than the atmospheric pressure so that it is possible to preventthe lubrication oil from leaking from the gap between the shaft 31 andthe oil bearing 21 under the action of the atmospheric pressure. Inaddition, the lubrication oil stored in the space 232 or the concaveportion 234 can also flow back to the oil bearing 21 due to gravity soas to maintain the amount of the lubrication oil contained in the oilbearing 21.

In addition, FIG. 5 is another schematic illustration showing thebearing structure of FIG. 3. The difference between FIGS. 5 and 3 isthat at least one groove 235 such as a ring-shaped groove is formed onthe inner wall of the through hole 231 of the cylindrical sealing member23 in FIG. 5. The groove 235 stores the leaked lubrication oil of theoil bearing 21 and prevents the lubrication oil from leaking from thegap between the shaft 31 and the oil bearing 21 under the action of theatmospheric pressure, because the pressure in the groove 235 is smallerthan the atmospheric pressure. In addition, the lubrication oil storedin the groove 235 can flow back to the oil bearing 21 due to gravity soas to maintain the amount of the lubrication oil contained in the oilbearing 21.

Furthermore, FIG. 6 is a schematic illustration showing a cover disposedon the bearing structure of FIG. 3. The difference between FIGS. 6 and 3is that the bearing structure 2 can further comprise a cover 25 disposedon the cylindrical sealing member 23, and the bearing structure 2 restsagainst at least one portion of an outer wall and/or a top surface ofthe cylindrical sealing member 23. As shown in FIG. 6, the cover 25 isadjacent to a concave portion 311 of the shaft 31 and a space 251 isformed between the cover 25 and the cylindrical sealing member 23. Thecover 25 is telescoped onto a side wall of the bearing tube to be fixedtherewith. The space 251 can prevent the vapor of the lubrication oilfrom leaking out so as to enhance the function of avoiding the oilleakage.

FIG. 7 is a schematic illustration showing at least one protrusionformed on the inner wall of the cylindrical sealing member of thebearing structure of FIG. 3. The difference between FIGS. 7 and 3 isthat an inner wall of the cylindrical sealing member 23 has at least oneprotrusion 236. The protrusion 236 rests against the sidewall 213 of theoil bearing 21. The protrusion 236 and the cylindrical sealing member 23are integrally formed. That is, the protrusion 236 and the cylindricalsealing member 23 form an integrated member. Of course, the protrusion236 and the cylindrical sealing member 23 can also be individuallyformed, and then the protrusion 236 is fixed to the inner wall of thecylindrical sealing member 23. As shown in FIG. 7, enabling theprotrusion 236 to rest against the oil bearing 21 reduces the precisionof manufacturing the cylindrical sealing member 23 and the oil bearing21 and the tolerances thereof so that the actual manufacturing processescan be easier. Of course, the protrusion 236 can also be disposed on theouter wall of the cylindrical sealing member 23 to rest against theinner wall of the bearing tube 32. Alternatively, the protrusion 236 canbe disposed on the sidewall 213 of the oil bearing 21 to rest againstthe inner wall of the cylindrical sealing member 23, or the protrusion236 can be disposed on the inner wall of the bearing tube 32 to restagainst the outer wall of the cylindrical sealing member 23.

FIG. 8 is a schematic illustration showing a bearing structurecooperated with a shaft and a bearing tube according to a secondembodiment of the invention. As shown in FIG. 8, a bearing structure 7according to the second embodiment of the invention is cooperated with ashaft 31 and is disposed in a bearing tube 32. The bearing structure 7comprises an oil bearing 21 and a sealing member 71. The structures andfunctions of the shaft 31, the bearing tube 32 and the oil bearing 21are the same as those mentioned herein above, and detailed descriptionsthereof will be omitted.

The sealing member 71 covers a top surface 212 of the oil bearing 21 andis connected to the inner wall of the bearing tube 32. The sealingmember 71 has a through hole 711 defined in its center. The diameter ofthe through hole 711 is substantially equal to or greater than that ofthe axial hole 211.

When the sealing member 71 covers the top surface 212 of the oil bearing21, the shaft 31 can pass through the through hole 711 and the axialhole 211, and the shaft 31 rests against the wear-resisting structure321. In addition, the inner wall of the through hole 711 is formed withat least one groove 712. The groove 712 can be a ring-shaped groovewhich stores the lubrication oil leaked from the oil bearing 21.

The bearing structure 7 of this embodiment has the sealing member 71covering the top surface 212 of the oil bearing 21 to form a closedspace. Therefore, it is possible to prevent the lubrication oil fromleaking from the top surface 212 of the oil bearing 21 and the gapbetween the oil bearing 21 and the bearing tube 32. Under the action ofthe atmospheric pressure, it is possible to prevent the lubrication oilfrom leaking from the gap between the shaft 31 and the oil bearing 21,and the lubrication oil stored in the groove 712 can properly flow backto the oil bearing 21 due to the gravity. Thus, the oil leakage can beavoided to effectively hold the lubrication oil in the oil bearing 21and thus lengthen the lifetime of the oil bearing 21. In addition, thebearing structure 7 of this embodiment can further comprise a cover 73,which rests against a top surface of the sealing member 71 and isadjacent to the concave portion 311 of the shaft 31 to form a space 731with the sealing member 71. The cover 73 is telescoped onto a side wallof the bearing tube to be fixed therewith. The space 731 can prevent theoil gas of the lubrication oil from leaking out so as to enhance theeffect of avoiding the oil leakage.

FIG. 9 is a schematic illustration showing a motor 8 according to thepreferred embodiment of the invention. In practice, the bearingstructure 2 or 7 can be applied to the motor 8. As shown in FIG. 9, thebearing structure 2 of FIG. 3 will be illustrated. The motor 8 comprisesa rotor structure 81, a stator structure 82 and a bearing structure 2.

The rotor structure 81 comprises a shaft 811 and a cover 812 as shown inFIG. 9. The shaft 811 is embedded into the cover 812. In addition, theshaft 811 and the cover 812 can also be integrally formed. That is, theshaft 811 and the cover 812 can form a single body. A magnet 813, whichcan be a permanent magnet, can be is attached to the inner surface ofthe cover 812. In this embodiment, the magnet 813 has a ring-shapedstructure and is disposed on the inner side of the cover 812.

The stator structure 82 has a bearing tube 821, a stator magnetic pole822 and a circuit board 823. The stator magnetic pole 822 is formed bywinding a coil or coils and is opposite to the magnet 813. Thealternating action of the magnetic field enables the rotor structure 81to move relative to the stator structure 82. The bearing tube 821 isinserted into a hole of the circuit board 823. A sensor is disposed onthe circuit board 823 to sense and control the magnetic field of thestator structure 82. In addition, the bearing tube 821 further has awear-resisting structure 824 such as a wear-resisting sheet. When theshaft 811 is axially mounted into the bearing tube 821, the shaft 811rests against the wear-resisting structure 824.

The bearing structure 2 is cooperated with the shaft 811 and disposed inthe bearing tube 821. The bearing structure 2 has an oil bearing 21 anda cylindrical sealing member 23. The oil bearing 21 has an axial hole211, and the shaft 811 passes through the axial hole 211.

The cylindrical sealing member 23 covers the top surface 212 and thesidewall 213 of the oil bearing 21, and is connected with the inner wallof the bearing tube 32. In addition, the cylindrical sealing member 23has a through hole 231 defined in its center. The diameter of thethrough hole 231 is substantially equal to or greater than that of theaxial hole 211. When the cylindrical sealing member 23 covers the oilbearing 21, the shaft 811 can pass through the through hole 231 and theaxial hole 211 and rest against the wear-resisting structure 824.

In this embodiment, the cylindrical sealing member 23 covers the topsurface 212 and the sidewall 213 of the oil bearing 21 to form a closedspace. Thus, it is possible to prevent the lubrication oil from leakingfrom the top surface 212 of the oil bearing 21 and the gap between theoil bearing 21 and the bearing tube 821. Under the action of theatmospheric pressure, it is possible to prevent the lubrication oil fromleaking from the gap between the shaft 811 and the oil bearing 21 sothat the oil leakage can be avoided, the lubrication oil can beeffectively held in the bearing structure 2, and the lifetime of themotor 8 can be lengthened.

FIG. 10 is a schematic illustration showing a fan 9 according to thepreferred embodiment of the invention. As shown in FIG. 10, the motor 8can be applied to the fan 9. The fan 9 comprises an impeller 91, a rotorstructure 81, a stator structure 82 and a bearing structure 2. The rotorstructure 81, the stator structure 82 and the bearing structure 2 havethe same structures and functions as those described hereinabove, sodetailed descriptions thereof will be omitted.

The impeller 91 is connected with the rotor structure 81 in thisembodiment. The impeller 91 comprises a hub 911 and at least one blade912, which is disposed on and connected with a circumference of the hub911. The fan 9 of this embodiment rotates the impeller 91 by the rotorstructure 81.

In summary, the fan, the motor and the bearing structure thereofaccording to the invention use the cylindrical sealing member or thesealing member with the groove to cover the oil bearing. Thus, theleakage path of the lubrication oil can be surely interrupted, so thatthe oil leakage can be avoided, and the lifetime of the oil bearing canbe lengthened.

Although the invention has been described with reference to specificembodiments; this description is not meant to be construed in a limitingsense. Various modifications of the disclosed embodiments, as well asalternative embodiments, will be apparent to persons skilled in the art.It is, therefore, contemplated that the appended claims will cover allmodifications that fall within the true scope of the invention.

1. A bearing structure disposed in a bearing tube, comprising: an oilbearing having an axial hole for being passed through by a shaft; and asealing member covering a top surface of the oil bearing and a sidewallof the oil bearing, wherein the sealing member has a through hole forbeing passed through by the shaft, and the sidewall of the oil bearingdoes not contact with the bearing tube.
 2. The bearing structureaccording to claim 1, further comprising a cover disposed on the sealingmember.
 3. The bearing structure according to claim 2, wherein an innerwall of the through hole is formed with at least one groove.
 4. Thebearing structure according to claim 2, wherein the cover rests againstthe sealing member to form a space between the cover and the sealingmember.
 5. The bearing structure according to claim 2, wherein the coveris telescoped onto a sidewall of the bearing tube.
 6. The bearingstructure according to claim 5, wherein the cover contacts at least oneportion of an outer wall of the sealing member and/or at least oneportion of a top surface of the sealing member.
 7. The bearing structureaccording to claim 5, wherein the cover is disposed adjacent to aconcave portion of the shaft.
 8. The bearing structure according toclaim 1, wherein the sealing member comprises a stepped portion todefine a space between the sealing member and the top surface of the oilbearing.
 9. The bearing structure according to claim 1, wherein an innerwall of the sealing structure has at least one protrusion restingagainst the sidewall of the oil bearing.
 10. The bearing structureaccording to claim 1, wherein the sidewall of the sealing member has atleast one protrusion resting against the sidewall of the oil bearing.11. The bearing structure according to claim 1, wherein the bearingstructure is applied in a fan or motor.
 12. A bearing structure disposedin a bearing tube, comprising: an oil bearing having an axial hole forbeing passed through by a shaft; and a sealing member covering a topsurface of the oil bearing, wherein the sealing member has a throughhole for being passed through by the shaft, and a sidewall of the oilbearing does not contact with the bearing tube.
 13. The bearingstructure according to claim 12, further comprising a cover disposed onthe sealing member.
 14. The bearing structure according to claim 13,wherein an inner wall of the through hole is formed with at least onegroove.
 15. The bearing structure according to claim 13, wherein thecover rests against the sealing member to form a space between the coverand the sealing member.
 16. The bearing structure according to claim 13,wherein the cover is telescoped onto a sidewall of the bearing tube. 17.The bearing structure according to claim 16, wherein the cover contactsat least one portion of an outer wall of the sealing member and/or atleast one portion of a top surface of the sealing member.
 18. Thebearing structure according to claim 16, wherein the cover is disposedadjacent to a concave portion of the shaft.
 19. The bearing structureaccording to claim 12, wherein a bottom portion of the bearing tube hasa wear-resisting structure resting against the shaft.
 20. The bearingstructure according to claim 12, wherein the bearing structure isapplied in a fan or motor.